Imported Upstream version 1.4upstream/1.4

1 files changed, 1987 insertions, 0 deletions

diff --git a/src/database/sql/sql_test.go b/src/database/sql/sql_test.go
new file mode 100644
index 000000000..34efdf254
--- /dev/null
+++ b/src/database/sql/sql_test.go
@@ -0,0 +1,1987 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package sql
+
+import (
+	"database/sql/driver"
+	"errors"
+	"fmt"
+	"math/rand"
+	"reflect"
+	"runtime"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+)
+
+func init() {
+	type dbConn struct {
+		db *DB
+		c  *driverConn
+	}
+	freedFrom := make(map[dbConn]string)
+	putConnHook = func(db *DB, c *driverConn) {
+		idx := -1
+		for i, v := range db.freeConn {
+			if v == c {
+				idx = i
+				break
+			}
+		}
+		if idx >= 0 {
+			// print before panic, as panic may get lost due to conflicting panic
+			// (all goroutines asleep) elsewhere, since we might not unlock
+			// the mutex in freeConn here.
+			println("double free of conn. conflicts are:\nA) " + freedFrom[dbConn{db, c}] + "\n\nand\nB) " + stack())
+			panic("double free of conn.")
+		}
+		freedFrom[dbConn{db, c}] = stack()
+	}
+}
+
+const fakeDBName = "foo"
+
+var chrisBirthday = time.Unix(123456789, 0)
+
+func newTestDB(t testing.TB, name string) *DB {
+	db, err := Open("test", fakeDBName)
+	if err != nil {
+		t.Fatalf("Open: %v", err)
+	}
+	if _, err := db.Exec("WIPE"); err != nil {
+		t.Fatalf("exec wipe: %v", err)
+	}
+	if name == "people" {
+		exec(t, db, "CREATE|people|name=string,age=int32,photo=blob,dead=bool,bdate=datetime")
+		exec(t, db, "INSERT|people|name=Alice,age=?,photo=APHOTO", 1)
+		exec(t, db, "INSERT|people|name=Bob,age=?,photo=BPHOTO", 2)
+		exec(t, db, "INSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?", 3, chrisBirthday)
+	}
+	if name == "magicquery" {
+		// Magic table name and column, known by fakedb_test.go.
+		exec(t, db, "CREATE|magicquery|op=string,millis=int32")
+		exec(t, db, "INSERT|magicquery|op=sleep,millis=10")
+	}
+	return db
+}
+
+func exec(t testing.TB, db *DB, query string, args ...interface{}) {
+	_, err := db.Exec(query, args...)
+	if err != nil {
+		t.Fatalf("Exec of %q: %v", query, err)
+	}
+}
+
+func closeDB(t testing.TB, db *DB) {
+	if e := recover(); e != nil {
+		fmt.Printf("Panic: %v\n", e)
+		panic(e)
+	}
+	defer setHookpostCloseConn(nil)
+	setHookpostCloseConn(func(_ *fakeConn, err error) {
+		if err != nil {
+			t.Errorf("Error closing fakeConn: %v", err)
+		}
+	})
+	for i, dc := range db.freeConn {
+		if n := len(dc.openStmt); n > 0 {
+			// Just a sanity check. This is legal in
+			// general, but if we make the tests clean up
+			// their statements first, then we can safely
+			// verify this is always zero here, and any
+			// other value is a leak.
+			t.Errorf("while closing db, freeConn %d/%d had %d open stmts; want 0", i, len(db.freeConn), n)
+		}
+	}
+	err := db.Close()
+	if err != nil {
+		t.Fatalf("error closing DB: %v", err)
+	}
+	db.mu.Lock()
+	count := db.numOpen
+	db.mu.Unlock()
+	if count != 0 {
+		t.Fatalf("%d connections still open after closing DB", db.numOpen)
+	}
+}
+
+// numPrepares assumes that db has exactly 1 idle conn and returns
+// its count of calls to Prepare
+func numPrepares(t *testing.T, db *DB) int {
+	if n := len(db.freeConn); n != 1 {
+		t.Fatalf("free conns = %d; want 1", n)
+	}
+	return db.freeConn[0].ci.(*fakeConn).numPrepare
+}
+
+func (db *DB) numDeps() int {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	return len(db.dep)
+}
+
+// Dependencies are closed via a goroutine, so this polls waiting for
+// numDeps to fall to want, waiting up to d.
+func (db *DB) numDepsPollUntil(want int, d time.Duration) int {
+	deadline := time.Now().Add(d)
+	for {
+		n := db.numDeps()
+		if n <= want || time.Now().After(deadline) {
+			return n
+		}
+		time.Sleep(50 * time.Millisecond)
+	}
+}
+
+func (db *DB) numFreeConns() int {
+	db.mu.Lock()
+	defer db.mu.Unlock()
+	return len(db.freeConn)
+}
+
+func (db *DB) dumpDeps(t *testing.T) {
+	for fc := range db.dep {
+		db.dumpDep(t, 0, fc, map[finalCloser]bool{})
+	}
+}
+
+func (db *DB) dumpDep(t *testing.T, depth int, dep finalCloser, seen map[finalCloser]bool) {
+	seen[dep] = true
+	indent := strings.Repeat("  ", depth)
+	ds := db.dep[dep]
+	for k := range ds {
+		t.Logf("%s%T (%p) waiting for -> %T (%p)", indent, dep, dep, k, k)
+		if fc, ok := k.(finalCloser); ok {
+			if !seen[fc] {
+				db.dumpDep(t, depth+1, fc, seen)
+			}
+		}
+	}
+}
+
+func TestQuery(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	prepares0 := numPrepares(t, db)
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	type row struct {
+		age  int
+		name string
+	}
+	got := []row{}
+	for rows.Next() {
+		var r row
+		err = rows.Scan(&r.age, &r.name)
+		if err != nil {
+			t.Fatalf("Scan: %v", err)
+		}
+		got = append(got, r)
+	}
+	err = rows.Err()
+	if err != nil {
+		t.Fatalf("Err: %v", err)
+	}
+	want := []row{
+		{age: 1, name: "Alice"},
+		{age: 2, name: "Bob"},
+		{age: 3, name: "Chris"},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
+	}
+
+	// And verify that the final rows.Next() call, which hit EOF,
+	// also closed the rows connection.
+	if n := db.numFreeConns(); n != 1 {
+		t.Fatalf("free conns after query hitting EOF = %d; want 1", n)
+	}
+	if prepares := numPrepares(t, db) - prepares0; prepares != 1 {
+		t.Errorf("executed %d Prepare statements; want 1", prepares)
+	}
+}
+
+func TestByteOwnership(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|name,photo|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	type row struct {
+		name  []byte
+		photo RawBytes
+	}
+	got := []row{}
+	for rows.Next() {
+		var r row
+		err = rows.Scan(&r.name, &r.photo)
+		if err != nil {
+			t.Fatalf("Scan: %v", err)
+		}
+		got = append(got, r)
+	}
+	corruptMemory := []byte("\xffPHOTO")
+	want := []row{
+		{name: []byte("Alice"), photo: corruptMemory},
+		{name: []byte("Bob"), photo: corruptMemory},
+		{name: []byte("Chris"), photo: corruptMemory},
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Errorf("mismatch.\n got: %#v\nwant: %#v", got, want)
+	}
+
+	var photo RawBytes
+	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
+	if err == nil {
+		t.Error("want error scanning into RawBytes from QueryRow")
+	}
+}
+
+func TestRowsColumns(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatalf("Query: %v", err)
+	}
+	cols, err := rows.Columns()
+	if err != nil {
+		t.Fatalf("Columns: %v", err)
+	}
+	want := []string{"age", "name"}
+	if !reflect.DeepEqual(cols, want) {
+		t.Errorf("got %#v; want %#v", cols, want)
+	}
+	if err := rows.Close(); err != nil {
+		t.Errorf("error closing rows: %s", err)
+	}
+}
+
+func TestQueryRow(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	var name string
+	var age int
+	var birthday time.Time
+
+	err := db.QueryRow("SELECT|people|age,name|age=?", 3).Scan(&age)
+	if err == nil || !strings.Contains(err.Error(), "expected 2 destination arguments") {
+		t.Errorf("expected error from wrong number of arguments; actually got: %v", err)
+	}
+
+	err = db.QueryRow("SELECT|people|bdate|age=?", 3).Scan(&birthday)
+	if err != nil || !birthday.Equal(chrisBirthday) {
+		t.Errorf("chris birthday = %v, err = %v; want %v", birthday, err, chrisBirthday)
+	}
+
+	err = db.QueryRow("SELECT|people|age,name|age=?", 2).Scan(&age, &name)
+	if err != nil {
+		t.Fatalf("age QueryRow+Scan: %v", err)
+	}
+	if name != "Bob" {
+		t.Errorf("expected name Bob, got %q", name)
+	}
+	if age != 2 {
+		t.Errorf("expected age 2, got %d", age)
+	}
+
+	err = db.QueryRow("SELECT|people|age,name|name=?", "Alice").Scan(&age, &name)
+	if err != nil {
+		t.Fatalf("name QueryRow+Scan: %v", err)
+	}
+	if name != "Alice" {
+		t.Errorf("expected name Alice, got %q", name)
+	}
+	if age != 1 {
+		t.Errorf("expected age 1, got %d", age)
+	}
+
+	var photo []byte
+	err = db.QueryRow("SELECT|people|photo|name=?", "Alice").Scan(&photo)
+	if err != nil {
+		t.Fatalf("photo QueryRow+Scan: %v", err)
+	}
+	want := []byte("APHOTO")
+	if !reflect.DeepEqual(photo, want) {
+		t.Errorf("photo = %q; want %q", photo, want)
+	}
+}
+
+func TestStatementErrorAfterClose(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age|name=?")
+	if err != nil {
+		t.Fatalf("Prepare: %v", err)
+	}
+	err = stmt.Close()
+	if err != nil {
+		t.Fatalf("Close: %v", err)
+	}
+	var name string
+	err = stmt.QueryRow("foo").Scan(&name)
+	if err == nil {
+		t.Errorf("expected error from QueryRow.Scan after Stmt.Close")
+	}
+}
+
+func TestStatementQueryRow(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age|name=?")
+	if err != nil {
+		t.Fatalf("Prepare: %v", err)
+	}
+	defer stmt.Close()
+	var age int
+	for n, tt := range []struct {
+		name string
+		want int
+	}{
+		{"Alice", 1},
+		{"Bob", 2},
+		{"Chris", 3},
+	} {
+		if err := stmt.QueryRow(tt.name).Scan(&age); err != nil {
+			t.Errorf("%d: on %q, QueryRow/Scan: %v", n, tt.name, err)
+		} else if age != tt.want {
+			t.Errorf("%d: age=%d, want %d", n, age, tt.want)
+		}
+	}
+}
+
+// golang.org/issue/3734
+func TestStatementQueryRowConcurrent(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	stmt, err := db.Prepare("SELECT|people|age|name=?")
+	if err != nil {
+		t.Fatalf("Prepare: %v", err)
+	}
+	defer stmt.Close()
+
+	const n = 10
+	ch := make(chan error, n)
+	for i := 0; i < n; i++ {
+		go func() {
+			var age int
+			err := stmt.QueryRow("Alice").Scan(&age)
+			if err == nil && age != 1 {
+				err = fmt.Errorf("unexpected age %d", age)
+			}
+			ch <- err
+		}()
+	}
+	for i := 0; i < n; i++ {
+		if err := <-ch; err != nil {
+			t.Error(err)
+		}
+	}
+}
+
+// just a test of fakedb itself
+func TestBogusPreboundParameters(t *testing.T) {
+	db := newTestDB(t, "foo")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	_, err := db.Prepare("INSERT|t1|name=?,age=bogusconversion")
+	if err == nil {
+		t.Fatalf("expected error")
+	}
+	if err.Error() != `fakedb: invalid conversion to int32 from "bogusconversion"` {
+		t.Errorf("unexpected error: %v", err)
+	}
+}
+
+func TestExec(t *testing.T) {
+	db := newTestDB(t, "foo")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Errorf("Stmt, err = %v, %v", stmt, err)
+	}
+	defer stmt.Close()
+
+	type execTest struct {
+		args    []interface{}
+		wantErr string
+	}
+	execTests := []execTest{
+		// Okay:
+		{[]interface{}{"Brad", 31}, ""},
+		{[]interface{}{"Brad", int64(31)}, ""},
+		{[]interface{}{"Bob", "32"}, ""},
+		{[]interface{}{7, 9}, ""},
+
+		// Invalid conversions:
+		{[]interface{}{"Brad", int64(0xFFFFFFFF)}, "sql: converting argument #1's type: sql/driver: value 4294967295 overflows int32"},
+		{[]interface{}{"Brad", "strconv fail"}, "sql: converting argument #1's type: sql/driver: value \"strconv fail\" can't be converted to int32"},
+
+		// Wrong number of args:
+		{[]interface{}{}, "sql: expected 2 arguments, got 0"},
+		{[]interface{}{1, 2, 3}, "sql: expected 2 arguments, got 3"},
+	}
+	for n, et := range execTests {
+		_, err := stmt.Exec(et.args...)
+		errStr := ""
+		if err != nil {
+			errStr = err.Error()
+		}
+		if errStr != et.wantErr {
+			t.Errorf("stmt.Execute #%d: for %v, got error %q, want error %q",
+				n, et.args, errStr, et.wantErr)
+		}
+	}
+}
+
+func TestTxPrepare(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatalf("Begin = %v", err)
+	}
+	stmt, err := tx.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Fatalf("Stmt, err = %v, %v", stmt, err)
+	}
+	defer stmt.Close()
+	_, err = stmt.Exec("Bobby", 7)
+	if err != nil {
+		t.Fatalf("Exec = %v", err)
+	}
+	err = tx.Commit()
+	if err != nil {
+		t.Fatalf("Commit = %v", err)
+	}
+	// Commit() should have closed the statement
+	if !stmt.closed {
+		t.Fatal("Stmt not closed after Commit")
+	}
+}
+
+func TestTxStmt(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Fatalf("Stmt, err = %v, %v", stmt, err)
+	}
+	defer stmt.Close()
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatalf("Begin = %v", err)
+	}
+	txs := tx.Stmt(stmt)
+	defer txs.Close()
+	_, err = txs.Exec("Bobby", 7)
+	if err != nil {
+		t.Fatalf("Exec = %v", err)
+	}
+	err = tx.Commit()
+	if err != nil {
+		t.Fatalf("Commit = %v", err)
+	}
+	// Commit() should have closed the statement
+	if !txs.closed {
+		t.Fatal("Stmt not closed after Commit")
+	}
+}
+
+// Issue: http://golang.org/issue/2784
+// This test didn't fail before because we got lucky with the fakedb driver.
+// It was failing, and now not, in github.com/bradfitz/go-sql-test
+func TestTxQuery(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	exec(t, db, "INSERT|t1|name=Alice")
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	r, err := tx.Query("SELECT|t1|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r.Close()
+
+	if !r.Next() {
+		if r.Err() != nil {
+			t.Fatal(r.Err())
+		}
+		t.Fatal("expected one row")
+	}
+
+	var x string
+	err = r.Scan(&x)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestTxQueryInvalid(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	_, err = tx.Query("SELECT|t1|name|")
+	if err == nil {
+		t.Fatal("Error expected")
+	}
+}
+
+// Tests fix for issue 4433, that retries in Begin happen when
+// conn.Begin() returns ErrBadConn
+func TestTxErrBadConn(t *testing.T) {
+	db, err := Open("test", fakeDBName+";badConn")
+	if err != nil {
+		t.Fatalf("Open: %v", err)
+	}
+	if _, err := db.Exec("WIPE"); err != nil {
+		t.Fatalf("exec wipe: %v", err)
+	}
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+	stmt, err := db.Prepare("INSERT|t1|name=?,age=?")
+	if err != nil {
+		t.Fatalf("Stmt, err = %v, %v", stmt, err)
+	}
+	defer stmt.Close()
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatalf("Begin = %v", err)
+	}
+	txs := tx.Stmt(stmt)
+	defer txs.Close()
+	_, err = txs.Exec("Bobby", 7)
+	if err != nil {
+		t.Fatalf("Exec = %v", err)
+	}
+	err = tx.Commit()
+	if err != nil {
+		t.Fatalf("Commit = %v", err)
+	}
+}
+
+// Tests fix for issue 2542, that we release a lock when querying on
+// a closed connection.
+func TestIssue2542Deadlock(t *testing.T) {
+	db := newTestDB(t, "people")
+	closeDB(t, db)
+	for i := 0; i < 2; i++ {
+		_, err := db.Query("SELECT|people|age,name|")
+		if err == nil {
+			t.Fatalf("expected error")
+		}
+	}
+}
+
+// From golang.org/issue/3865
+func TestCloseStmtBeforeRows(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	s, err := db.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r, err := s.Query()
+	if err != nil {
+		s.Close()
+		t.Fatal(err)
+	}
+
+	err = s.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r.Close()
+}
+
+// Tests fix for issue 2788, that we bind nil to a []byte if the
+// value in the column is sql null
+func TestNullByteSlice(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t|id=int32,name=nullstring")
+	exec(t, db, "INSERT|t|id=10,name=?", nil)
+
+	var name []byte
+
+	err := db.QueryRow("SELECT|t|name|id=?", 10).Scan(&name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if name != nil {
+		t.Fatalf("name []byte should be nil for null column value, got: %#v", name)
+	}
+
+	exec(t, db, "INSERT|t|id=11,name=?", "bob")
+	err = db.QueryRow("SELECT|t|name|id=?", 11).Scan(&name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(name) != "bob" {
+		t.Fatalf("name []byte should be bob, got: %q", string(name))
+	}
+}
+
+func TestPointerParamsAndScans(t *testing.T) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t|id=int32,name=nullstring")
+
+	bob := "bob"
+	var name *string
+
+	name = &bob
+	exec(t, db, "INSERT|t|id=10,name=?", name)
+	name = nil
+	exec(t, db, "INSERT|t|id=20,name=?", name)
+
+	err := db.QueryRow("SELECT|t|name|id=?", 10).Scan(&name)
+	if err != nil {
+		t.Fatalf("querying id 10: %v", err)
+	}
+	if name == nil {
+		t.Errorf("id 10's name = nil; want bob")
+	} else if *name != "bob" {
+		t.Errorf("id 10's name = %q; want bob", *name)
+	}
+
+	err = db.QueryRow("SELECT|t|name|id=?", 20).Scan(&name)
+	if err != nil {
+		t.Fatalf("querying id 20: %v", err)
+	}
+	if name != nil {
+		t.Errorf("id 20 = %q; want nil", *name)
+	}
+}
+
+func TestQueryRowClosingStmt(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	var name string
+	var age int
+	err := db.QueryRow("SELECT|people|age,name|age=?", 3).Scan(&age, &name)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(db.freeConn) != 1 {
+		t.Fatalf("expected 1 free conn")
+	}
+	fakeConn := db.freeConn[0].ci.(*fakeConn)
+	if made, closed := fakeConn.stmtsMade, fakeConn.stmtsClosed; made != closed {
+		t.Errorf("statement close mismatch: made %d, closed %d", made, closed)
+	}
+}
+
+// Test issue 6651
+func TestIssue6651(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	var v string
+
+	want := "error in rows.Next"
+	rowsCursorNextHook = func(dest []driver.Value) error {
+		return fmt.Errorf(want)
+	}
+	defer func() { rowsCursorNextHook = nil }()
+	err := db.QueryRow("SELECT|people|name|").Scan(&v)
+	if err == nil || err.Error() != want {
+		t.Errorf("error = %q; want %q", err, want)
+	}
+	rowsCursorNextHook = nil
+
+	want = "error in rows.Close"
+	rowsCloseHook = func(rows *Rows, err *error) {
+		*err = fmt.Errorf(want)
+	}
+	defer func() { rowsCloseHook = nil }()
+	err = db.QueryRow("SELECT|people|name|").Scan(&v)
+	if err == nil || err.Error() != want {
+		t.Errorf("error = %q; want %q", err, want)
+	}
+}
+
+type nullTestRow struct {
+	nullParam    interface{}
+	notNullParam interface{}
+	scanNullVal  interface{}
+}
+
+type nullTestSpec struct {
+	nullType    string
+	notNullType string
+	rows        [6]nullTestRow
+}
+
+func TestNullStringParam(t *testing.T) {
+	spec := nullTestSpec{"nullstring", "string", [6]nullTestRow{
+		{NullString{"aqua", true}, "", NullString{"aqua", true}},
+		{NullString{"brown", false}, "", NullString{"", false}},
+		{"chartreuse", "", NullString{"chartreuse", true}},
+		{NullString{"darkred", true}, "", NullString{"darkred", true}},
+		{NullString{"eel", false}, "", NullString{"", false}},
+		{"foo", NullString{"black", false}, nil},
+	}}
+	nullTestRun(t, spec)
+}
+
+func TestNullInt64Param(t *testing.T) {
+	spec := nullTestSpec{"nullint64", "int64", [6]nullTestRow{
+		{NullInt64{31, true}, 1, NullInt64{31, true}},
+		{NullInt64{-22, false}, 1, NullInt64{0, false}},
+		{22, 1, NullInt64{22, true}},
+		{NullInt64{33, true}, 1, NullInt64{33, true}},
+		{NullInt64{222, false}, 1, NullInt64{0, false}},
+		{0, NullInt64{31, false}, nil},
+	}}
+	nullTestRun(t, spec)
+}
+
+func TestNullFloat64Param(t *testing.T) {
+	spec := nullTestSpec{"nullfloat64", "float64", [6]nullTestRow{
+		{NullFloat64{31.2, true}, 1, NullFloat64{31.2, true}},
+		{NullFloat64{13.1, false}, 1, NullFloat64{0, false}},
+		{-22.9, 1, NullFloat64{-22.9, true}},
+		{NullFloat64{33.81, true}, 1, NullFloat64{33.81, true}},
+		{NullFloat64{222, false}, 1, NullFloat64{0, false}},
+		{10, NullFloat64{31.2, false}, nil},
+	}}
+	nullTestRun(t, spec)
+}
+
+func TestNullBoolParam(t *testing.T) {
+	spec := nullTestSpec{"nullbool", "bool", [6]nullTestRow{
+		{NullBool{false, true}, true, NullBool{false, true}},
+		{NullBool{true, false}, false, NullBool{false, false}},
+		{true, true, NullBool{true, true}},
+		{NullBool{true, true}, false, NullBool{true, true}},
+		{NullBool{true, false}, true, NullBool{false, false}},
+		{true, NullBool{true, false}, nil},
+	}}
+	nullTestRun(t, spec)
+}
+
+func nullTestRun(t *testing.T, spec nullTestSpec) {
+	db := newTestDB(t, "")
+	defer closeDB(t, db)
+	exec(t, db, fmt.Sprintf("CREATE|t|id=int32,name=string,nullf=%s,notnullf=%s", spec.nullType, spec.notNullType))
+
+	// Inserts with db.Exec:
+	exec(t, db, "INSERT|t|id=?,name=?,nullf=?,notnullf=?", 1, "alice", spec.rows[0].nullParam, spec.rows[0].notNullParam)
+	exec(t, db, "INSERT|t|id=?,name=?,nullf=?,notnullf=?", 2, "bob", spec.rows[1].nullParam, spec.rows[1].notNullParam)
+
+	// Inserts with a prepared statement:
+	stmt, err := db.Prepare("INSERT|t|id=?,name=?,nullf=?,notnullf=?")
+	if err != nil {
+		t.Fatalf("prepare: %v", err)
+	}
+	defer stmt.Close()
+	if _, err := stmt.Exec(3, "chris", spec.rows[2].nullParam, spec.rows[2].notNullParam); err != nil {
+		t.Errorf("exec insert chris: %v", err)
+	}
+	if _, err := stmt.Exec(4, "dave", spec.rows[3].nullParam, spec.rows[3].notNullParam); err != nil {
+		t.Errorf("exec insert dave: %v", err)
+	}
+	if _, err := stmt.Exec(5, "eleanor", spec.rows[4].nullParam, spec.rows[4].notNullParam); err != nil {
+		t.Errorf("exec insert eleanor: %v", err)
+	}
+
+	// Can't put null val into non-null col
+	if _, err := stmt.Exec(6, "bob", spec.rows[5].nullParam, spec.rows[5].notNullParam); err == nil {
+		t.Errorf("expected error inserting nil val with prepared statement Exec")
+	}
+
+	_, err = db.Exec("INSERT|t|id=?,name=?,nullf=?", 999, nil, nil)
+	if err == nil {
+		// TODO: this test fails, but it's just because
+		// fakeConn implements the optional Execer interface,
+		// so arguably this is the correct behavior.  But
+		// maybe I should flesh out the fakeConn.Exec
+		// implementation so this properly fails.
+		// t.Errorf("expected error inserting nil name with Exec")
+	}
+
+	paramtype := reflect.TypeOf(spec.rows[0].nullParam)
+	bindVal := reflect.New(paramtype).Interface()
+
+	for i := 0; i < 5; i++ {
+		id := i + 1
+		if err := db.QueryRow("SELECT|t|nullf|id=?", id).Scan(bindVal); err != nil {
+			t.Errorf("id=%d Scan: %v", id, err)
+		}
+		bindValDeref := reflect.ValueOf(bindVal).Elem().Interface()
+		if !reflect.DeepEqual(bindValDeref, spec.rows[i].scanNullVal) {
+			t.Errorf("id=%d got %#v, want %#v", id, bindValDeref, spec.rows[i].scanNullVal)
+		}
+	}
+}
+
+// golang.org/issue/4859
+func TestQueryRowNilScanDest(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	var name *string // nil pointer
+	err := db.QueryRow("SELECT|people|name|").Scan(name)
+	want := "sql: Scan error on column index 0: destination pointer is nil"
+	if err == nil || err.Error() != want {
+		t.Errorf("error = %q; want %q", err.Error(), want)
+	}
+}
+
+func TestIssue4902(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	driver := db.driver.(*fakeDriver)
+	opens0 := driver.openCount
+
+	var stmt *Stmt
+	var err error
+	for i := 0; i < 10; i++ {
+		stmt, err = db.Prepare("SELECT|people|name|")
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = stmt.Close()
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	opens := driver.openCount - opens0
+	if opens > 1 {
+		t.Errorf("opens = %d; want <= 1", opens)
+		t.Logf("db = %#v", db)
+		t.Logf("driver = %#v", driver)
+		t.Logf("stmt = %#v", stmt)
+	}
+}
+
+// Issue 3857
+// This used to deadlock.
+func TestSimultaneousQueries(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer tx.Rollback()
+
+	r1, err := tx.Query("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r1.Close()
+
+	r2, err := tx.Query("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer r2.Close()
+}
+
+func TestMaxIdleConns(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	tx, err := db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tx.Commit()
+	if got := len(db.freeConn); got != 1 {
+		t.Errorf("freeConns = %d; want 1", got)
+	}
+
+	db.SetMaxIdleConns(0)
+
+	if got := len(db.freeConn); got != 0 {
+		t.Errorf("freeConns after set to zero = %d; want 0", got)
+	}
+
+	tx, err = db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	tx.Commit()
+	if got := len(db.freeConn); got != 0 {
+		t.Errorf("freeConns = %d; want 0", got)
+	}
+}
+
+func TestMaxOpenConns(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+	defer setHookpostCloseConn(nil)
+	setHookpostCloseConn(func(_ *fakeConn, err error) {
+		if err != nil {
+			t.Errorf("Error closing fakeConn: %v", err)
+		}
+	})
+
+	db := newTestDB(t, "magicquery")
+	defer closeDB(t, db)
+
+	driver := db.driver.(*fakeDriver)
+
+	// Force the number of open connections to 0 so we can get an accurate
+	// count for the test
+	db.SetMaxIdleConns(0)
+
+	if g, w := db.numFreeConns(), 0; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(0, time.Second); n > 0 {
+		t.Errorf("number of dependencies = %d; expected 0", n)
+		db.dumpDeps(t)
+	}
+
+	driver.mu.Lock()
+	opens0 := driver.openCount
+	closes0 := driver.closeCount
+	driver.mu.Unlock()
+
+	db.SetMaxIdleConns(10)
+	db.SetMaxOpenConns(10)
+
+	stmt, err := db.Prepare("SELECT|magicquery|op|op=?,millis=?")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Start 50 parallel slow queries.
+	const (
+		nquery      = 50
+		sleepMillis = 25
+		nbatch      = 2
+	)
+	var wg sync.WaitGroup
+	for batch := 0; batch < nbatch; batch++ {
+		for i := 0; i < nquery; i++ {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				var op string
+				if err := stmt.QueryRow("sleep", sleepMillis).Scan(&op); err != nil && err != ErrNoRows {
+					t.Error(err)
+				}
+			}()
+		}
+		// Sleep for twice the expected length of time for the
+		// batch of 50 queries above to finish before starting
+		// the next round.
+		time.Sleep(2 * sleepMillis * time.Millisecond)
+	}
+	wg.Wait()
+
+	if g, w := db.numFreeConns(), 10; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(20, time.Second); n > 20 {
+		t.Errorf("number of dependencies = %d; expected <= 20", n)
+		db.dumpDeps(t)
+	}
+
+	driver.mu.Lock()
+	opens := driver.openCount - opens0
+	closes := driver.closeCount - closes0
+	driver.mu.Unlock()
+
+	if opens > 10 {
+		t.Logf("open calls = %d", opens)
+		t.Logf("close calls = %d", closes)
+		t.Errorf("db connections opened = %d; want <= 10", opens)
+		db.dumpDeps(t)
+	}
+
+	if err := stmt.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	if g, w := db.numFreeConns(), 10; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(10, time.Second); n > 10 {
+		t.Errorf("number of dependencies = %d; expected <= 10", n)
+		db.dumpDeps(t)
+	}
+
+	db.SetMaxOpenConns(5)
+
+	if g, w := db.numFreeConns(), 5; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(5, time.Second); n > 5 {
+		t.Errorf("number of dependencies = %d; expected 0", n)
+		db.dumpDeps(t)
+	}
+
+	db.SetMaxOpenConns(0)
+
+	if g, w := db.numFreeConns(), 5; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(5, time.Second); n > 5 {
+		t.Errorf("number of dependencies = %d; expected 0", n)
+		db.dumpDeps(t)
+	}
+
+	db.SetMaxIdleConns(0)
+
+	if g, w := db.numFreeConns(), 0; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(0, time.Second); n > 0 {
+		t.Errorf("number of dependencies = %d; expected 0", n)
+		db.dumpDeps(t)
+	}
+}
+
+func TestSingleOpenConn(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	db.SetMaxOpenConns(1)
+
+	rows, err := db.Query("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = rows.Close(); err != nil {
+		t.Fatal(err)
+	}
+	// shouldn't deadlock
+	rows, err = db.Query("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = rows.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// golang.org/issue/5323
+func TestStmtCloseDeps(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+	defer setHookpostCloseConn(nil)
+	setHookpostCloseConn(func(_ *fakeConn, err error) {
+		if err != nil {
+			t.Errorf("Error closing fakeConn: %v", err)
+		}
+	})
+
+	db := newTestDB(t, "magicquery")
+	defer closeDB(t, db)
+
+	driver := db.driver.(*fakeDriver)
+
+	driver.mu.Lock()
+	opens0 := driver.openCount
+	closes0 := driver.closeCount
+	driver.mu.Unlock()
+	openDelta0 := opens0 - closes0
+
+	stmt, err := db.Prepare("SELECT|magicquery|op|op=?,millis=?")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Start 50 parallel slow queries.
+	const (
+		nquery      = 50
+		sleepMillis = 25
+		nbatch      = 2
+	)
+	var wg sync.WaitGroup
+	for batch := 0; batch < nbatch; batch++ {
+		for i := 0; i < nquery; i++ {
+			wg.Add(1)
+			go func() {
+				defer wg.Done()
+				var op string
+				if err := stmt.QueryRow("sleep", sleepMillis).Scan(&op); err != nil && err != ErrNoRows {
+					t.Error(err)
+				}
+			}()
+		}
+		// Sleep for twice the expected length of time for the
+		// batch of 50 queries above to finish before starting
+		// the next round.
+		time.Sleep(2 * sleepMillis * time.Millisecond)
+	}
+	wg.Wait()
+
+	if g, w := db.numFreeConns(), 2; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(4, time.Second); n > 4 {
+		t.Errorf("number of dependencies = %d; expected <= 4", n)
+		db.dumpDeps(t)
+	}
+
+	driver.mu.Lock()
+	opens := driver.openCount - opens0
+	closes := driver.closeCount - closes0
+	openDelta := (driver.openCount - driver.closeCount) - openDelta0
+	driver.mu.Unlock()
+
+	if openDelta > 2 {
+		t.Logf("open calls = %d", opens)
+		t.Logf("close calls = %d", closes)
+		t.Logf("open delta = %d", openDelta)
+		t.Errorf("db connections opened = %d; want <= 2", openDelta)
+		db.dumpDeps(t)
+	}
+
+	if len(stmt.css) > nquery {
+		t.Errorf("len(stmt.css) = %d; want <= %d", len(stmt.css), nquery)
+	}
+
+	if err := stmt.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	if g, w := db.numFreeConns(), 2; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(2, time.Second); n > 2 {
+		t.Errorf("number of dependencies = %d; expected <= 2", n)
+		db.dumpDeps(t)
+	}
+
+	db.SetMaxIdleConns(0)
+
+	if g, w := db.numFreeConns(), 0; g != w {
+		t.Errorf("free conns = %d; want %d", g, w)
+	}
+
+	if n := db.numDepsPollUntil(0, time.Second); n > 0 {
+		t.Errorf("number of dependencies = %d; expected 0", n)
+		db.dumpDeps(t)
+	}
+}
+
+// golang.org/issue/5046
+func TestCloseConnBeforeStmts(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	defer setHookpostCloseConn(nil)
+	setHookpostCloseConn(func(_ *fakeConn, err error) {
+		if err != nil {
+			t.Errorf("Error closing fakeConn: %v; from %s", err, stack())
+			db.dumpDeps(t)
+			t.Errorf("DB = %#v", db)
+		}
+	})
+
+	stmt, err := db.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(db.freeConn) != 1 {
+		t.Fatalf("expected 1 freeConn; got %d", len(db.freeConn))
+	}
+	dc := db.freeConn[0]
+	if dc.closed {
+		t.Errorf("conn shouldn't be closed")
+	}
+
+	if n := len(dc.openStmt); n != 1 {
+		t.Errorf("driverConn num openStmt = %d; want 1", n)
+	}
+	err = db.Close()
+	if err != nil {
+		t.Errorf("db Close = %v", err)
+	}
+	if !dc.closed {
+		t.Errorf("after db.Close, driverConn should be closed")
+	}
+	if n := len(dc.openStmt); n != 0 {
+		t.Errorf("driverConn num openStmt = %d; want 0", n)
+	}
+
+	err = stmt.Close()
+	if err != nil {
+		t.Errorf("Stmt close = %v", err)
+	}
+
+	if !dc.closed {
+		t.Errorf("conn should be closed")
+	}
+	if dc.ci != nil {
+		t.Errorf("after Stmt Close, driverConn's Conn interface should be nil")
+	}
+}
+
+// golang.org/issue/5283: don't release the Rows' connection in Close
+// before calling Stmt.Close.
+func TestRowsCloseOrder(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	db.SetMaxIdleConns(0)
+	setStrictFakeConnClose(t)
+	defer setStrictFakeConnClose(nil)
+
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = rows.Close()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestRowsImplicitClose(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	rows, err := db.Query("SELECT|people|age,name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	want, fail := 2, errors.New("fail")
+	r := rows.rowsi.(*rowsCursor)
+	r.errPos, r.err = want, fail
+
+	got := 0
+	for rows.Next() {
+		got++
+	}
+	if got != want {
+		t.Errorf("got %d rows, want %d", got, want)
+	}
+	if err := rows.Err(); err != fail {
+		t.Errorf("got error %v, want %v", err, fail)
+	}
+	if !r.closed {
+		t.Errorf("r.closed is false, want true")
+	}
+}
+
+func TestStmtCloseOrder(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	db.SetMaxIdleConns(0)
+	setStrictFakeConnClose(t)
+	defer setStrictFakeConnClose(nil)
+
+	_, err := db.Query("SELECT|non_existent|name|")
+	if err == nil {
+		t.Fatal("Quering non-existent table should fail")
+	}
+}
+
+// golang.org/issue/5781
+func TestErrBadConnReconnect(t *testing.T) {
+	db := newTestDB(t, "foo")
+	defer closeDB(t, db)
+	exec(t, db, "CREATE|t1|name=string,age=int32,dead=bool")
+
+	simulateBadConn := func(name string, hook *func() bool, op func() error) {
+		broken, retried := false, false
+		numOpen := db.numOpen
+
+		// simulate a broken connection on the first try
+		*hook = func() bool {
+			if !broken {
+				broken = true
+				return true
+			}
+			retried = true
+			return false
+		}
+
+		if err := op(); err != nil {
+			t.Errorf(name+": %v", err)
+			return
+		}
+
+		if !broken || !retried {
+			t.Error(name + ": Failed to simulate broken connection")
+		}
+		*hook = nil
+
+		if numOpen != db.numOpen {
+			t.Errorf(name+": leaked %d connection(s)!", db.numOpen-numOpen)
+			numOpen = db.numOpen
+		}
+	}
+
+	// db.Exec
+	dbExec := func() error {
+		_, err := db.Exec("INSERT|t1|name=?,age=?,dead=?", "Gordon", 3, true)
+		return err
+	}
+	simulateBadConn("db.Exec prepare", &hookPrepareBadConn, dbExec)
+	simulateBadConn("db.Exec exec", &hookExecBadConn, dbExec)
+
+	// db.Query
+	dbQuery := func() error {
+		rows, err := db.Query("SELECT|t1|age,name|")
+		if err == nil {
+			err = rows.Close()
+		}
+		return err
+	}
+	simulateBadConn("db.Query prepare", &hookPrepareBadConn, dbQuery)
+	simulateBadConn("db.Query query", &hookQueryBadConn, dbQuery)
+
+	// db.Prepare
+	simulateBadConn("db.Prepare", &hookPrepareBadConn, func() error {
+		stmt, err := db.Prepare("INSERT|t1|name=?,age=?,dead=?")
+		if err != nil {
+			return err
+		}
+		stmt.Close()
+		return nil
+	})
+
+	// Provide a way to force a re-prepare of a statement on next execution
+	forcePrepare := func(stmt *Stmt) {
+		stmt.css = nil
+	}
+
+	// stmt.Exec
+	stmt1, err := db.Prepare("INSERT|t1|name=?,age=?,dead=?")
+	if err != nil {
+		t.Fatalf("prepare: %v", err)
+	}
+	defer stmt1.Close()
+	// make sure we must prepare the stmt first
+	forcePrepare(stmt1)
+
+	stmtExec := func() error {
+		_, err := stmt1.Exec("Gopher", 3, false)
+		return err
+	}
+	simulateBadConn("stmt.Exec prepare", &hookPrepareBadConn, stmtExec)
+	simulateBadConn("stmt.Exec exec", &hookExecBadConn, stmtExec)
+
+	// stmt.Query
+	stmt2, err := db.Prepare("SELECT|t1|age,name|")
+	if err != nil {
+		t.Fatalf("prepare: %v", err)
+	}
+	defer stmt2.Close()
+	// make sure we must prepare the stmt first
+	forcePrepare(stmt2)
+
+	stmtQuery := func() error {
+		rows, err := stmt2.Query()
+		if err == nil {
+			err = rows.Close()
+		}
+		return err
+	}
+	simulateBadConn("stmt.Query prepare", &hookPrepareBadConn, stmtQuery)
+	simulateBadConn("stmt.Query exec", &hookQueryBadConn, stmtQuery)
+}
+
+type concurrentTest interface {
+	init(t testing.TB, db *DB)
+	finish(t testing.TB)
+	test(t testing.TB) error
+}
+
+type concurrentDBQueryTest struct {
+	db *DB
+}
+
+func (c *concurrentDBQueryTest) init(t testing.TB, db *DB) {
+	c.db = db
+}
+
+func (c *concurrentDBQueryTest) finish(t testing.TB) {
+	c.db = nil
+}
+
+func (c *concurrentDBQueryTest) test(t testing.TB) error {
+	rows, err := c.db.Query("SELECT|people|name|")
+	if err != nil {
+		t.Error(err)
+		return err
+	}
+	var name string
+	for rows.Next() {
+		rows.Scan(&name)
+	}
+	rows.Close()
+	return nil
+}
+
+type concurrentDBExecTest struct {
+	db *DB
+}
+
+func (c *concurrentDBExecTest) init(t testing.TB, db *DB) {
+	c.db = db
+}
+
+func (c *concurrentDBExecTest) finish(t testing.TB) {
+	c.db = nil
+}
+
+func (c *concurrentDBExecTest) test(t testing.TB) error {
+	_, err := c.db.Exec("NOSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?", 3, chrisBirthday)
+	if err != nil {
+		t.Error(err)
+		return err
+	}
+	return nil
+}
+
+type concurrentStmtQueryTest struct {
+	db   *DB
+	stmt *Stmt
+}
+
+func (c *concurrentStmtQueryTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.stmt, err = db.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentStmtQueryTest) finish(t testing.TB) {
+	if c.stmt != nil {
+		c.stmt.Close()
+		c.stmt = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentStmtQueryTest) test(t testing.TB) error {
+	rows, err := c.stmt.Query()
+	if err != nil {
+		t.Errorf("error on query:  %v", err)
+		return err
+	}
+
+	var name string
+	for rows.Next() {
+		rows.Scan(&name)
+	}
+	rows.Close()
+	return nil
+}
+
+type concurrentStmtExecTest struct {
+	db   *DB
+	stmt *Stmt
+}
+
+func (c *concurrentStmtExecTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.stmt, err = db.Prepare("NOSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentStmtExecTest) finish(t testing.TB) {
+	if c.stmt != nil {
+		c.stmt.Close()
+		c.stmt = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentStmtExecTest) test(t testing.TB) error {
+	_, err := c.stmt.Exec(3, chrisBirthday)
+	if err != nil {
+		t.Errorf("error on exec:  %v", err)
+		return err
+	}
+	return nil
+}
+
+type concurrentTxQueryTest struct {
+	db *DB
+	tx *Tx
+}
+
+func (c *concurrentTxQueryTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.tx, err = c.db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentTxQueryTest) finish(t testing.TB) {
+	if c.tx != nil {
+		c.tx.Rollback()
+		c.tx = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentTxQueryTest) test(t testing.TB) error {
+	rows, err := c.db.Query("SELECT|people|name|")
+	if err != nil {
+		t.Error(err)
+		return err
+	}
+	var name string
+	for rows.Next() {
+		rows.Scan(&name)
+	}
+	rows.Close()
+	return nil
+}
+
+type concurrentTxExecTest struct {
+	db *DB
+	tx *Tx
+}
+
+func (c *concurrentTxExecTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.tx, err = c.db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentTxExecTest) finish(t testing.TB) {
+	if c.tx != nil {
+		c.tx.Rollback()
+		c.tx = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentTxExecTest) test(t testing.TB) error {
+	_, err := c.tx.Exec("NOSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?", 3, chrisBirthday)
+	if err != nil {
+		t.Error(err)
+		return err
+	}
+	return nil
+}
+
+type concurrentTxStmtQueryTest struct {
+	db   *DB
+	tx   *Tx
+	stmt *Stmt
+}
+
+func (c *concurrentTxStmtQueryTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.tx, err = c.db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.stmt, err = c.tx.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentTxStmtQueryTest) finish(t testing.TB) {
+	if c.stmt != nil {
+		c.stmt.Close()
+		c.stmt = nil
+	}
+	if c.tx != nil {
+		c.tx.Rollback()
+		c.tx = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentTxStmtQueryTest) test(t testing.TB) error {
+	rows, err := c.stmt.Query()
+	if err != nil {
+		t.Errorf("error on query:  %v", err)
+		return err
+	}
+
+	var name string
+	for rows.Next() {
+		rows.Scan(&name)
+	}
+	rows.Close()
+	return nil
+}
+
+type concurrentTxStmtExecTest struct {
+	db   *DB
+	tx   *Tx
+	stmt *Stmt
+}
+
+func (c *concurrentTxStmtExecTest) init(t testing.TB, db *DB) {
+	c.db = db
+	var err error
+	c.tx, err = c.db.Begin()
+	if err != nil {
+		t.Fatal(err)
+	}
+	c.stmt, err = c.tx.Prepare("NOSERT|people|name=Chris,age=?,photo=CPHOTO,bdate=?")
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func (c *concurrentTxStmtExecTest) finish(t testing.TB) {
+	if c.stmt != nil {
+		c.stmt.Close()
+		c.stmt = nil
+	}
+	if c.tx != nil {
+		c.tx.Rollback()
+		c.tx = nil
+	}
+	c.db = nil
+}
+
+func (c *concurrentTxStmtExecTest) test(t testing.TB) error {
+	_, err := c.stmt.Exec(3, chrisBirthday)
+	if err != nil {
+		t.Errorf("error on exec:  %v", err)
+		return err
+	}
+	return nil
+}
+
+type concurrentRandomTest struct {
+	tests []concurrentTest
+}
+
+func (c *concurrentRandomTest) init(t testing.TB, db *DB) {
+	c.tests = []concurrentTest{
+		new(concurrentDBQueryTest),
+		new(concurrentDBExecTest),
+		new(concurrentStmtQueryTest),
+		new(concurrentStmtExecTest),
+		new(concurrentTxQueryTest),
+		new(concurrentTxExecTest),
+		new(concurrentTxStmtQueryTest),
+		new(concurrentTxStmtExecTest),
+	}
+	for _, ct := range c.tests {
+		ct.init(t, db)
+	}
+}
+
+func (c *concurrentRandomTest) finish(t testing.TB) {
+	for _, ct := range c.tests {
+		ct.finish(t)
+	}
+}
+
+func (c *concurrentRandomTest) test(t testing.TB) error {
+	ct := c.tests[rand.Intn(len(c.tests))]
+	return ct.test(t)
+}
+
+func doConcurrentTest(t testing.TB, ct concurrentTest) {
+	maxProcs, numReqs := 1, 500
+	if testing.Short() {
+		maxProcs, numReqs = 4, 50
+	}
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(maxProcs))
+
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	ct.init(t, db)
+	defer ct.finish(t)
+
+	var wg sync.WaitGroup
+	wg.Add(numReqs)
+
+	reqs := make(chan bool)
+	defer close(reqs)
+
+	for i := 0; i < maxProcs*2; i++ {
+		go func() {
+			for range reqs {
+				err := ct.test(t)
+				if err != nil {
+					wg.Done()
+					continue
+				}
+				wg.Done()
+			}
+		}()
+	}
+
+	for i := 0; i < numReqs; i++ {
+		reqs <- true
+	}
+
+	wg.Wait()
+}
+
+func manyConcurrentQueries(t testing.TB) {
+	maxProcs, numReqs := 16, 500
+	if testing.Short() {
+		maxProcs, numReqs = 4, 50
+	}
+	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(maxProcs))
+
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	stmt, err := db.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer stmt.Close()
+
+	var wg sync.WaitGroup
+	wg.Add(numReqs)
+
+	reqs := make(chan bool)
+	defer close(reqs)
+
+	for i := 0; i < maxProcs*2; i++ {
+		go func() {
+			for range reqs {
+				rows, err := stmt.Query()
+				if err != nil {
+					t.Errorf("error on query:  %v", err)
+					wg.Done()
+					continue
+				}
+
+				var name string
+				for rows.Next() {
+					rows.Scan(&name)
+				}
+				rows.Close()
+
+				wg.Done()
+			}
+		}()
+	}
+
+	for i := 0; i < numReqs; i++ {
+		reqs <- true
+	}
+
+	wg.Wait()
+}
+
+func TestIssue6081(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+
+	drv := db.driver.(*fakeDriver)
+	drv.mu.Lock()
+	opens0 := drv.openCount
+	closes0 := drv.closeCount
+	drv.mu.Unlock()
+
+	stmt, err := db.Prepare("SELECT|people|name|")
+	if err != nil {
+		t.Fatal(err)
+	}
+	rowsCloseHook = func(rows *Rows, err *error) {
+		*err = driver.ErrBadConn
+	}
+	defer func() { rowsCloseHook = nil }()
+	for i := 0; i < 10; i++ {
+		rows, err := stmt.Query()
+		if err != nil {
+			t.Fatal(err)
+		}
+		rows.Close()
+	}
+	if n := len(stmt.css); n > 1 {
+		t.Errorf("len(css slice) = %d; want <= 1", n)
+	}
+	stmt.Close()
+	if n := len(stmt.css); n != 0 {
+		t.Errorf("len(css slice) after Close = %d; want 0", n)
+	}
+
+	drv.mu.Lock()
+	opens := drv.openCount - opens0
+	closes := drv.closeCount - closes0
+	drv.mu.Unlock()
+	if opens < 9 {
+		t.Errorf("opens = %d; want >= 9", opens)
+	}
+	if closes < 9 {
+		t.Errorf("closes = %d; want >= 9", closes)
+	}
+}
+
+func TestConcurrency(t *testing.T) {
+	doConcurrentTest(t, new(concurrentDBQueryTest))
+	doConcurrentTest(t, new(concurrentDBExecTest))
+	doConcurrentTest(t, new(concurrentStmtQueryTest))
+	doConcurrentTest(t, new(concurrentStmtExecTest))
+	doConcurrentTest(t, new(concurrentTxQueryTest))
+	doConcurrentTest(t, new(concurrentTxExecTest))
+	doConcurrentTest(t, new(concurrentTxStmtQueryTest))
+	doConcurrentTest(t, new(concurrentTxStmtExecTest))
+	doConcurrentTest(t, new(concurrentRandomTest))
+}
+
+func TestConnectionLeak(t *testing.T) {
+	db := newTestDB(t, "people")
+	defer closeDB(t, db)
+	// Start by opening defaultMaxIdleConns
+	rows := make([]*Rows, defaultMaxIdleConns)
+	// We need to SetMaxOpenConns > MaxIdleConns, so the DB can open
+	// a new connection and we can fill the idle queue with the released
+	// connections.
+	db.SetMaxOpenConns(len(rows) + 1)
+	for ii := range rows {
+		r, err := db.Query("SELECT|people|name|")
+		if err != nil {
+			t.Fatal(err)
+		}
+		r.Next()
+		if err := r.Err(); err != nil {
+			t.Fatal(err)
+		}
+		rows[ii] = r
+	}
+	// Now we have defaultMaxIdleConns busy connections. Open
+	// a new one, but wait until the busy connections are released
+	// before returning control to DB.
+	drv := db.driver.(*fakeDriver)
+	drv.waitCh = make(chan struct{}, 1)
+	drv.waitingCh = make(chan struct{}, 1)
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		r, err := db.Query("SELECT|people|name|")
+		if err != nil {
+			t.Fatal(err)
+		}
+		r.Close()
+		wg.Done()
+	}()
+	// Wait until the goroutine we've just created has started waiting.
+	<-drv.waitingCh
+	// Now close the busy connections. This provides a connection for
+	// the blocked goroutine and then fills up the idle queue.
+	for _, v := range rows {
+		v.Close()
+	}
+	// At this point we give the new connection to DB. This connection is
+	// now useless, since the idle queue is full and there are no pending
+	// requests. DB should deal with this situation without leaking the
+	// connection.
+	drv.waitCh <- struct{}{}
+	wg.Wait()
+}
+
+func BenchmarkConcurrentDBExec(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentDBExecTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentStmtQuery(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentStmtQueryTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentStmtExec(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentStmtExecTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentTxQuery(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentTxQueryTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentTxExec(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentTxExecTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentTxStmtQuery(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentTxStmtQueryTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentTxStmtExec(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentTxStmtExecTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}
+
+func BenchmarkConcurrentRandom(b *testing.B) {
+	b.ReportAllocs()
+	ct := new(concurrentRandomTest)
+	for i := 0; i < b.N; i++ {
+		doConcurrentTest(b, ct)
+	}
+}